Flow cytometry is a technique that allows for the rapid separation, counting, and characterization of individual cells and is routinely used in clinical and laboratory settings for a variety of applications. The technology relies on directing a beam of light onto a hydrodynamically-focused stream of liquid. A number of detectors are then aimed at the point where the stream passes through the light beam: one in line with the light beam (Forward Scatter or FSC) and several perpendicular to it (Side Scatter or SSC). FSC correlates with the cell volume and SSC depends on the inner complexity of the particle (e.g., shape of the nucleus, the amount and type of cytoplasmic granules or the membrane roughness). As a result of these correlations, different specific cell types exhibit different FSC and SSC, allowing cell types to be distinguished in flow cytometry.
The ability to identify specific cell types, however, relies on proper calibration of the instrument, a process that has relied on the use of purified cells of the cell type of interest. Obtaining these purified cells can require costly, laborious procedures that are prone to batch-to-batch variation. Therefore, there is a need in the art for synthetic compositions with tunable optical properties that can mimic specific cell types in devices such as flow cytometers.